src/tethering.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2010  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <unistd.h>
  27 #include <stdio.h>
  28 #include <sys/ioctl.h>
  29 #include <net/if.h>
  30 #include <linux/sockios.h>
  31
  32 #include "connman.h"
  33
  34 #include <gdhcp/gdhcp.h>
  35
  36 #define BRIDGE_NAME "tether"
  37 #define BRIDGE_IP "192.168.218.1"
  38 #define BRIDGE_BCAST "192.168.218.255"
  39 #define BRIDGE_SUBNET "255.255.255.0"
  40 #define BRIDGE_IP_START "192.168.218.100"
  41 #define BRIDGE_IP_END "192.168.218.200"
  42 #define BRIDGE_DNS "8.8.8.8"
  43
  44 static connman_bool_t tethering_status = FALSE;
  45 static char *default_interface = NULL;
  46 static volatile gint tethering_enabled;
  47 static GDHCPServer *tethering_dhcp_server = NULL;
  48
  49 connman_bool_t __connman_tethering_get_status(void)
  50 {
  51         return tethering_status;
  52 }
  53
  54
  55 static void dhcp_server_debug(const char *str, void *data)
  56 {
  57         connman_info("%s: %s\n", (const char *) data, str);
  58 }
  59
  60 static void dhcp_server_error(GDHCPServerError error)
  61 {
  62         switch (error) {
  63         case G_DHCP_SERVER_ERROR_NONE:
  64                 connman_error("OK");
  65                 break;
  66         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
  67                 connman_error("Interface unavailable");
  68                 break;
  69         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
  70                 connman_error("Interface in use");
  71                 break;
  72         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
  73                 connman_error("Interface down");
  74                 break;
  75         case G_DHCP_SERVER_ERROR_NOMEM:
  76                 connman_error("No memory");
  77                 break;
  78         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
  79                 connman_error("Invalid index");
  80                 break;
  81         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
  82                 connman_error("Invalid option");
  83                 break;
  84         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
  85                 connman_error("Invalid address");
  86                 break;
  87         }
  88 }
  89
  90 static GDHCPServer *dhcp_server_start(const char *bridge,
  91                                 const char *router, const char* subnet,
  92                                 const char *start_ip, const char *end_ip,
  93                                 unsigned int lease_time, const char *dns)
  94 {
  95         GDHCPServerError error;
  96         GDHCPServer *dhcp_server;
  97         int index;
  98
  99         DBG("");
 100
 101         index = connman_inet_ifindex(bridge);
 102         if (index < 0)
 103                 return NULL;
 104
 105         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 106         if (dhcp_server == NULL) {
 107                 dhcp_server_error(error);
 108                 return NULL;
 109         }
 110
 111         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 112
 113         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 114         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 115         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 116         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 117         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 118
 119         g_dhcp_server_start(dhcp_server);
 120
 121         return dhcp_server;
 122 }
 123
 124 static void dhcp_server_stop(GDHCPServer *server)
 125 {
 126         if (server == NULL)
 127                 return;
 128
 129         g_dhcp_server_unref(server);
 130 }
 131
 132 static int set_forward_delay(const char *name, unsigned int delay)
 133 {
 134         FILE *f;
 135         char *forward_delay_path;
 136
 137         forward_delay_path =
 138                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 139
 140         if (forward_delay_path == NULL)
 141                 return -ENOMEM;
 142
 143         f = fopen(forward_delay_path, "r+");
 144
 145         g_free(forward_delay_path);
 146
 147         if (f == NULL)
 148                 return -errno;
 149
 150         fprintf(f, "%d", delay);
 151
 152         fclose(f);
 153
 154         return 0;
 155 }
 156
 157 static int create_bridge(const char *name)
 158 {
 159         int sk, err;
 160
 161         DBG("name %s", name);
 162
 163         sk = socket(AF_INET, SOCK_STREAM, 0);
 164         if (sk < 0)
 165                 return -EOPNOTSUPP;
 166
 167         err = ioctl(sk, SIOCBRADDBR, name);
 168
 169         if (err < 0)
 170                 return -EOPNOTSUPP;
 171
 172         err = set_forward_delay(name, 0);
 173
 174         if (err < 0)
 175                 ioctl(sk, SIOCBRDELBR, name);
 176
 177         close(sk);
 178
 179         return err;
 180 }
 181
 182 static int remove_bridge(const char *name)
 183 {
 184         int sk, err;
 185
 186         DBG("name %s", name);
 187
 188         sk = socket(AF_INET, SOCK_STREAM, 0);
 189         if (sk < 0)
 190                 return -EOPNOTSUPP;
 191
 192         err = ioctl(sk, SIOCBRDELBR, name);
 193
 194         close(sk);
 195
 196         if (err < 0)
 197                 return -EOPNOTSUPP;
 198
 199         return 0;
 200 }
 201
 202 static int enable_bridge(const char *name)
 203 {
 204         int err, index;
 205
 206         index = connman_inet_ifindex(name);
 207         if (index < 0)
 208                 return index;
 209
 210         err = __connman_inet_modify_address(RTM_NEWADDR,
 211                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 212                                             BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 213         if (err < 0)
 214                 return err;
 215
 216         return connman_inet_ifup(index);
 217 }
 218
 219 static int disable_bridge(const char *name)
 220 {
 221         int index;
 222
 223         index = connman_inet_ifindex(name);
 224         if (index < 0)
 225                 return index;
 226
 227         return connman_inet_ifdown(index);
 228 }
 229
 230 static int enable_ip_forward(connman_bool_t enable)
 231 {
 232
 233         FILE *f;
 234
 235         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 236         if (f == NULL)
 237                 return -errno;
 238
 239         if (enable == TRUE)
 240                 fprintf(f, "1");
 241         else
 242                 fprintf(f, "0");
 243
 244         fclose(f);
 245
 246         return 0;
 247 }
 248
 249 static int enable_nat(const char *interface)
 250 {
 251         int err;
 252
 253         if (interface == NULL)
 254                 return 0;
 255
 256         /* Enable IPv4 forwarding */
 257         err = enable_ip_forward(TRUE);
 258         if (err < 0)
 259                 return err;
 260
 261         /* POSTROUTING flush */
 262         err = __connman_iptables_command("-t nat -F POSTROUTING");
 263         if (err < 0)
 264                 return err;
 265
 266         /* Enable masquerading */
 267         err = __connman_iptables_command("-t nat -A POSTROUTING "
 268                                         "-o %s -j MASQUERADE", interface);
 269         if (err < 0)
 270                 return err;
 271
 272         return __connman_iptables_commit("nat");
 273 }
 274
 275 static void disable_nat(const char *interface)
 276 {
 277         int err;
 278
 279         /* Disable IPv4 forwarding */
 280         enable_ip_forward(FALSE);
 281
 282         /* POSTROUTING flush */
 283         err = __connman_iptables_command("-t nat -F POSTROUTING");
 284         if (err < 0)
 285                 return;
 286
 287         __connman_iptables_commit("nat");
 288 }
 289
 290 void __connman_tethering_set_enabled(void)
 291 {
 292         int err;
 293
 294         if (tethering_status == FALSE)
 295                 return;
 296
 297         DBG("enabled %d", tethering_enabled + 1);
 298
 299         if (g_atomic_int_exchange_and_add(&tethering_enabled, 1) == 0) {
 300                 err = create_bridge(BRIDGE_NAME);
 301                 if (err < 0)
 302                         return;
 303
 304                 err = enable_bridge(BRIDGE_NAME);
 305                 if (err < 0) {
 306                         remove_bridge(BRIDGE_NAME);
 307                         return;
 308                 }
 309
 310                 tethering_dhcp_server =
 311                         dhcp_server_start(BRIDGE_NAME,
 312                                                 BRIDGE_IP, BRIDGE_SUBNET,
 313                                                 BRIDGE_IP_START, BRIDGE_IP_END,
 314                                                         24 * 3600, BRIDGE_DNS);
 315                 if (tethering_dhcp_server == NULL) {
 316                         disable_bridge(BRIDGE_NAME);
 317                         remove_bridge(BRIDGE_NAME);
 318                         return;
 319                 }
 320
 321                 enable_nat(default_interface);
 322
 323                 DBG("tethering started");
 324         }
 325 }
 326
 327 void __connman_tethering_set_disabled(void)
 328 {
 329         if (tethering_status == TRUE)
 330                 return;
 331
 332         DBG("enabled %d", tethering_enabled - 1);
 333
 334         if (g_atomic_int_dec_and_test(&tethering_enabled) == TRUE) {
 335                 disable_nat(default_interface);
 336
 337                 dhcp_server_stop(tethering_dhcp_server);
 338
 339                 disable_bridge(BRIDGE_NAME);
 340
 341                 remove_bridge(BRIDGE_NAME);
 342
 343                 DBG("tethering stopped");
 344         }
 345 }
 346
 347 int __connman_tethering_set_status(connman_bool_t status)
 348 {
 349         if (status == tethering_status)
 350                 return -EALREADY;
 351
 352         tethering_status = status;
 353
 354         if (status == TRUE)
 355                 __connman_technology_enable_tethering(BRIDGE_NAME);
 356         else
 357                 __connman_technology_disable_tethering(BRIDGE_NAME);
 358
 359         return 0;
 360 }
 361
 362 void __connman_tethering_update_interface(const char *interface)
 363 {
 364         DBG("interface %s", interface);
 365
 366         g_free(default_interface);
 367
 368         if (interface == NULL) {
 369                 disable_nat(interface);
 370                 default_interface = NULL;
 371
 372                 return;
 373         }
 374
 375         default_interface = g_strdup(interface);
 376
 377         if (tethering_status == FALSE ||
 378                         !g_atomic_int_get(&tethering_enabled))
 379                 return;
 380
 381         enable_nat(interface);
 382 }
 383
 384 int __connman_tethering_init(void)
 385 {
 386         DBG("");
 387
 388         tethering_enabled = 0;
 389
 390         return 0;
 391 }
 392
 393 void __connman_tethering_cleanup(void)
 394 {
 395         DBG("");
 396
 397         if (tethering_status == TRUE) {
 398                 if (tethering_dhcp_server)
 399                         dhcp_server_stop(tethering_dhcp_server);
 400                 disable_bridge(BRIDGE_NAME);
 401                 remove_bridge(BRIDGE_NAME);
 402         }
 403 }